Define division ring on trace-preserving endomorphisms. The
multiplication operation is reversed composition, per the definition of
E of [Crawley] p. 117, 4th line from
bottom. (Contributed by NM,
8-Jun-2013.)

Condition determining equality of two trace-preserving endomorphisms,
showing it is unnecessary to consider the identity translation. In
tendocan30280, we show that we only need to consider a
single non-identity
translation. (Contributed by NM, 21-Jun-2013.)

Trace-preserving property of endomorphism sum operation , based
on theorem trlco30183. Part of remark in [Crawley] p. 118, 2nd line,
"it is clear from the second part of G (our trlco30183) that Delta is a
subring of E." (In our development, we will bypass their E and go
directly to their Delta, whose base set is our
.) (Contributed by
NM, 9-Jun-2013.)

The base set of the division ring on trace-preserving endomorphisms is
the set of all trace-preserving endomorphisms (for a fiducial co-atom
). TODO: the
.t hypothesis isn't used. (Also look at others.)
(Contributed by NM, 9-Jun-2013.)

The base set of the division ring on trace-preserving endomorphisms is
the set of all trace-preserving endomorphisms (for a fiducial co-atom
).
(Contributed by NM, 9-Jun-2013.)
(New usage is discouraged.)